Twin Cities Carry Forum Archive

mangum primers
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Author:  wheatstraw [ Sun Jun 21, 2009 1:09 am ]
Post subject:  mangum primers

I'm new to reloading and have an idiot question for all the bright minds on this forum. It's been impossible to find small pistol primers these days but I have run across SP magnum primers. I've read a few posts (on other boards) saying that magnum primers are fine as long as you back off on the load. I'm loading 9mm and .38sp and will be very conservative starting out. I'm pretty careful and can do basic math (yay for an overpriced education!) so I'm not too concerned about screwing up...though I always reserve at least a 5% failure rate for anything I do. :)

Can anyone offer any advice? I'll take anything...even "you're a total idiot for considering this and should not be allowed to posses/operate a firearm".

Author:  DeanC [ Sun Jun 21, 2009 3:26 pm ]
Post subject:  Re: mangum primers

On the 38sp you should fine if you stick to starting loads only.

Things get dicier with the 9mm as it is much higher pressure round to begin with. I know people who have done it with the 9mm, but I wouldn't.

Author:  Rodentman [ Sun Jun 21, 2009 7:16 pm ]
Post subject:  Re: mangum primers

I have loaded 9mm and .40 with mag primers but have ceased doing so on the learned advice of others smarter than I.

When I run out of reg primers, no more 9 or 40, but I still have .38, .357, and the .44's I can work with.

Author:  72_chev_truck [ Wed Aug 12, 2009 5:29 pm ]
Post subject:  Re: mangum primers

I made the mistake of buying magnum SP for .40. I ended up loading them up anyways without knowing. Now I have almost 1000 cases with mag primers and about 100 cases with non mag primers all sorted together. :bang:

I ended up using 7 grains of HS-6 with the magnum primers, 180 grain flat point in a Glock 27 and did not notice any extreme pressure signs. It did throw a pretty good fireball out of the barrel though. I also tried half a mag of these and the rest of the mag with the SD loads and I was quite sure when I popped off the SD loads as it recoiled noticably harder.

If you do end up using them, work up a load and start low on your powder charts.

Author:  wheatstraw [ Wed Aug 12, 2009 10:39 pm ]
Post subject:  Re: mangum primers

I decided to take my chances and load some 9mm with magnum primers. To be extra careful, I backed the powder charge off 10% from the starting load in my manual. The load wasn't enough to cycle the slide on my xdm. :( thankfully I found some SP primers so I'll use those in 9mm and save the magnums for the .38.

Author:  bensdad [ Wed Aug 12, 2009 11:12 pm ]
Post subject:  Re: mangum primers

I've asked the same question before. Now that I have a better understanding of the process, I won't do it (load mag. spp) when the recipe doesn't call for it. By saying things like "back the load off 10%", or "start low on your powder charts", you're assuming that: A + B = C. This is not the case. The primer/powder/burn relationship is: A causes B which is a factor in C. They way ya'll seem to be looking at it, you imply that a mag. primer (or any primer) is a component of the preasure curve. That may be the case, but there's a LOT more to it than that. The primer IGNITES the powder. What if your mag. spp ignites the powder faster or more completely than a reg. spp? You may get a preasure spike that the gun can't handle. I'm not going to engage in a debate with people who have more reloading experience than I do (as someone may come along shortly and explain how I'm wrong). But, keep in mind, they write recipes for a reason. If it's not in a reloading book (and I've never seen a reloading book recommend what you're talking about), then maybe, just maybe, it's a dangerous idea.

Author:  Dick Unger [ Thu Aug 13, 2009 5:47 am ]
Post subject:  Re: mangum primers

In an inline muzzeloader a too hot primer can force the bullet ahead before the powder (or blackpowder substitute that we use) properly ignites, and it really affects accuraccy, and, I suppose, power and pressure. The muzzeloaders have heavy barrels which can handle pressure all the way to the end of the barrel.
Modern guns are not specially designed for homemade loads.

I know some "light" loads are dangerous and/or ineffective because the pressure can spike after the bullet is out in the barrrel.

Don't know if this might happen with magnum primers and modern powders but it's something to consider.

Author:  macphisto [ Thu Aug 13, 2009 8:11 am ]
Post subject:  Re: mangum primers


Read this thread, paying special attention to Seismic Sam's posts. He really knows his shit when it comes to reloading...and a lot of other things.

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